Effects of cage versus floor rearing system on goose intestinal histomorphology and cecal microbial composition

Due to the demand for modern goose production and the pressure of environmental protection, the rearing systems of geese are changing from traditional waterside rearing to intensive rearing systems such as floor rearing (FR) and cage rearing (CR) systems. However, little is known about the effects of different rearing systems on goose intestinal functions and cecal microbial composition. Therefore, this study aimed to compare intestinal histomorphology and cecal microbial composition differences in geese reared under CR and FR at 270 d of age. Histomorphological analysis showed that the ileal villus height (VH) to crypt depth (CD) ratio was significantly greater in CR than in FR (P < 0.001). Taxonomic analysis showed that the dominant bacteria of cecal microorganisms in both rearing systems were roughly similar, with Bacteroidota, Firmicutes, Fusobacteriota, and Proteobacteria being the dominant phyla while Bacteroides, Fusobacterium, and uncultured_bacterium_o_Bacteroidales being the dominant genera. Differentially abundant taxa between CR and FR were also identified using Linear Discriminant Analysis Effect Size (LEfSe) analysis (P < 0.05, LDA score > 3.5). Megamonas and Anaerobiospirillum were significantly enriched in the CR group at the genus level, while uncultured_bacterium_f_Rikenellaceae and Sutterella were significantly enriched in the FR group. Notably, we found that the relative abundance of uncultured_bacterium_f_Rikenellaceae was significantly negatively correlated with the ileal VH and VH/CD (P < 0.05). The relative abundance of Megamonas and Anaerobiospirillum were significantly negatively correlated with abdominal fat weight and relative abdominal fat weight (P < 0.01), whereas that of Sutterella was significantly positively correlated with abdominal fat weight and relative abdominal fat weight (P < 0.01). Furthermore, PICRUSt2 analysis indicated that the lipid metabolism pathways of cecal microorganisms were lower enriched in CR than in FR. In conclusion, compared with FR, the CR significantly changed goose ileal histomorphological characteristics and cecal microbial composition, thereby affecting goose physiological functions and production performance.